Love is a Joint Effort

After Harry and Severus come together as a family they have to face the threat of Voldemort returning. With Remus and Sirius by their sides, will they be able to stop his resurrection? And will jealousy wedge itself between father and son to separate what was bound in "Love is a Charm" and "Love is a Haven"? Severitus, no slash, Genfic, 4th year, Part three of "Love is..." series